Oak Gluing challenge-Help

[Jerry Olexa]

Have a cherished 30 yr old oak kitchen table I finished myself many years ago...As the years passed, a portion of the center support column has separated at one of the glue joints. As weight is applied to the top, it wobbles due to the 1/4-1/2" separation of the column glue joint. The joint widens as weight is placed on top...(see pics below).. I think a re-glue is in order. I have several strap clamps but the choice of glue concerns me. The old glue at this joint is difficult to access to scrape off/clean without thoroughly disassembling the total column and table which I'd prefer not to do.....Would an epoxy address this issue?..What do you guys recommend?? Hopefully, the pictures will show my dilemma....Thanks.

[Lee Schierer]

I wouldn't recommend epoxy. I would clean out as much glue as I can with a scraper and sandpaper. Spread the crack as wide as you can get it. If possible make a backer piece that fits tightly to the inside surface that will span the crack. Apply a liberal amount of glue and clamp the joint with as much pressure as you can apply. Band clamps may not exert enough pressure. Use bar clamps along wood bars that are perpendicular to the column to hold the joint closed. Use regular PVA type glue. Work the glue into small areas of the crack with dental floss.

[Mike Cutler]

Jerry

What is the original glue?

My first inclination is to go with some T-88 from System Three, or another type of structural epoxy.
You're going to need a gap filling adhesive. T-88 and other structural epoxies have this characteristic.

Lee
Why no to epoxy?

[Rob Woodman]

Hi Jerry, have you any ideas as to what glue was originally used?
Most don't play well together!;)

Aside from that question, from the photo's it would seem shrinkage may be the cause, if so you would be hard pressed to cramp it back up tight.
An alternative method would be to scrape out the open joint as best as possible and glue in tapered strips of oak,(not wedges) epoxy would be a good choice for this (West's system with micro bead filler added to improve gap filling capacity and strength). Pour the glue in the crack, coat the tapered strip and tap home, ensure it is wide enough to remain proud and plane/sand flush when glue is cured.
I have used this process to repair masts and booms on Dutch Sailing Barges to good effect.

Rob.

[Jerry Olexa]

I believe the glue used originally was a standard carpenter's wood glue...Not much residue...Looks slightly glossy, clear? I think I will be able to use standard Bar clamps and improvise around the jaw size...Just want to be sure the glue will work....Also considering a concealed metal fastener or two as I will turn unit upside down and access from below where it will not show....

[Lee Schierer]

Lee
Why no to epoxy?

I just don't care for epoxy. I don't think it bonds as well to wood as PVA glue. It also makes a mess that is harder to clean up than wiping down a joint with a damp rag.

[Tom Hammond]

That's a pretty substantial separation. I think I'd take the time to dissemble the table, turn the column upside down, jam a screwdriver into the crack to open it as much as possible, then clean out the crack... and would take my time on it. If you don't get good surfaces to reglue, you'll be doing this again. To clean out cracks like this in the past, I've taken a 6" piece of a hacksaw blade and ground the end so it tapers like a chisel. I figure I can't get a chisel in there, so I'll make one that can. It works pretty good, since all I'm doing is scraping and scratching. But, when you think you're done, you're probably only about halfway. Be sure to vac out the debris then reglue. I don't see anything wrong with an epoxy for this application, but... you MUST get this clamped up right or the glue won't hold it. If it "fights you" to close the crack, it's a lost battle anyway. Under those circumstances, I make a jig to hold the piece, partially close the crack (medium pressure) and rout a narrow (no more than a 1/4") dado on the crack, as deep as I can. Then I make a matching piece to fill the dado and glue it up. I agree with a previous comment... straps ain't gonna cut it. You're going to need bar clamps or the like. GOOD LUCK. Be sure to post pictures of the repair!!

[Pat Barry]

First, how are you going to clamp it to pull it back together? Will it pull back together? If so, I would spread it like previously suggested, and then gently scrape any loose material = don't go crazy with it though. I would then tape along the crack line to help control the glue squeeze out. Then I would wet it down, blow out the excess water, and fill it with Gorilla glue using a card or paper to get it in as deep as possible. Then clamp it. I would recommend re-inforce the bottom side of the column with a metal strap. Good luck.

[Darius Ferlas]

I'm not sure cleaning the glue and re-gluing along the very surfaces that failed, and with the same type of glue in the first place would be the best idea.

What about using some kind of dowel/domino/tenon contraption?

I definitely haven't given it a lot of thought but for now this is what I would consider doing:



remove loose debris/splinters from the crack using some kind of brush, but no to rough so it doesn't remove too much of healthy material
pour weldbond inside the crack so it fills the crack, it may not help a whole lot but it won't hurt.
clamp the crack shut as much as possible and give it 24+ hours, regular clamps for the octagon part, heavy duty tie-downs for the round part.
with the table upside down (clamps still on) drill 1/2" or bigger holes as deep as the height of the square part. Drill in 2 or 3 points along the line of the crack. My theory here is that drilling would expose new, undisturbed wood area which would be better for glue-up.
use appropriate width dowels, regular wood glue and drive them as deep as the holes allow. The gluing surface would be substantial and along the grain.
wait another 24 hours
say a prayer
remove clamps

Steps are numbered for easier reference, in case someone wants to pick a fight ;)

[Scott T Smith]

I believe that if it were me, I would disassemble the column, and split it in two along the glue line (sawing through it if necessary. Run the two pieces across a jointer and face joint them (minimal possible), and then reglue the two pieces together.

At the end of the day, this should provide the best appearance as well as the strongest bond.

[Dino Drosas]

My thoughts run along the same lines as Scott's. I have done this exact procedure on a ball and claw foot oak table base. Generally the legs are through-bolted onto the base for easy removal with access from the bottom. I cut mine on the band saw following the glue line with the split facing up and sawing through it. With careful set-up, you will be cutting the glue line on the opposite side. Sound like a lot of work but it isn't and most likely faster than trying to clean out the old glue. The results will be much better.

Dino Drosas

[David Cefai]

I had something similar. Table leg had 3 "feet" attached by sliding dovetails. The leg cracked and one dovetail was loose.

I cleaned off as much glue as I could and used West Systems epoxy with a filler to thicken it - make it thickish but liquid enough to get it deep into the crack.

Two years on the joint is still OK.

[Jerry Olexa]

What is your source for a good quality epoxy? Plan to upend the table Thursday and examine the possibilities from below. Also I'll test for ability to close the gap with bar clamps..I have a feeling these quality epoxies are not found in the nearby borg or hardware store..Like to know before i disrupt the kitchen normalcy by taking away the table..Thanks guys..All good tips..BTW what's your favorite epoxy? I'm hearing WEST is a good product...

[Bob Smalser]

I believe the glue used originally was a standard carpenter's wood glue...Not much residue...Looks slightly glossy, clear? I think I will be able to use standard Bar clamps and improvise around the jaw size...Just want to be sure the glue will work....Also considering a concealed metal fastener or two as I will turn unit upside down and access from below where it will not show....

Stop.

If the joint was originally glued using Titebond, Elmer's or some other yellow or white water-based PVA glue, then EPOXY WON'T STICK TO ITS RESIDUE.

http://pic20.picturetrail.com/VOL12/1104763/7738131/102357570.jpg

Nor will any other glue except those few with high levels of cyanoacrylates, which in pure form are way too brittle to use as general-purpose wood glues. So far, I've found that the only glue that will stick to PVA residue is PL Premium Construction Adhesive. I'm sure there are others, but I haven't tested them like I have PL.

http://pic20.picturetrail.com/VOL12/1104763/7738131/393289336.jpg

The next problem is why the joint failed. Because if it was a defect in one of the staves or assembly with the moisture content too high, then your pedestal isn't going to close using band clamps or Spanish Windlass....and even if it closes, it'll break again soon. If this is the case then you'll have to glue in a wedge and refinish.

In turn, if the joint failed because the table was set up over a forced-air heating duct, then move the table and let the wood reach moisture equilibrium before regluing.

If the joint failed because it was either starved of glue (or more likely in coopering, didn't get sufficient clamping pressure), then a reglue is in order. The best method is usually to disassemble, scrape new faying surfaces so as to remove old glue residue, and reassemble using fully repairable interior furniture glues like Urea Formaldehyde Plastic Resin or Hot Hide Glue....where 30 years from now if it fails again one of your children can steam the joint apart and repair it properly.

The moral is to stop using inappropriate glues unless you want somebody cussing your work several decades from now. You should plan for all crossgrain glue joints to eventually fail....because they all eventually will. In those, only fully repairable glues should be used. PVA's have only one use in fine furniture, and that's to layup panels....matching-grain joints that almost never fail given proper construction that lets them expand and contract across the grain..

Are Your Glue Joints Repairable?
http://www.sawmillcreek.org/showthread.php?t=21822

[Jerry Olexa]

Thank you Bob for your in depth analysis/reply..That link you furnished and wrote is valuable info. I'll put it to use in this project!! BTW what is a good source for the Urea Plastic resin or West Epoxy?? Very grateful for your help!!!

[Jerry Olexa]

Turned table upsidedown and inspected...Joint will come together and close when clamped..And I will be able to use bar Clamps....i also see a chance to rig up some inside bracing shaped to fit the pedestal...So its workable...All good.
Now need to separate and scrape and clean all surfaces before glue....Plus find a local source for a plastic resin, epoxy, specialized glue, etc...Think we can make it work..Choice of glue critical with proper prep/clamping..thanks to all.. I'll post pic later..

[Jerry Olexa]

Good news!! I located some Weldwood, improvised by making some inner crosswise braces to fit, Sanded off old glue using a rasp, used some hidden metal fasteners, and after gluing used bar clamps to hold together (one strap clamp for round area)...Later removed clamps and it did the job!!! Did some final touches today and a little more glue. In the morning, the table will be in use...This project concerned me as it was an old table with heavy use and you can only rework, reglue so much!! Thanks for your help!!! I'll try to get a pic or two later. A happy ending...

[David Cefai]

I (and a lot of other people) use West Systems. Expect to be out of pocket by $60 - 70 after buying the smallest can (750ml I think) and the microfibre filler.

It does however last for years unmixed.

When they say mix EXACTLY in these proportions they really, really mean it. Don't slosh teaspoons. I use disposable syringes. You can buy special pumps but they're pricey for occasional use.

If you get the mix wrong the stuff will not harden. Acetone gets it off (don't ask how I know :()

[Stephen Cherry]

I would make a piece of wood about the size of a paint stick, hardwood though, and cut it to be shaped like a knife edge. (make two)

Then glue sandpaper to each side, making a sandpapered knife. Cut into the crack, opening it up, and making it take the form of the sandpaper knife. Keep sawing away unit everyting is clean.

Then take the second piece of wood with the same shape as the first, and fit it in the crack.

Glue, clamp, and trim.